ceph/src/boost/libs/test/include/boost/test/utils/iterator/input_iterator_facade.hpp

   1 //  (C) Copyright Gennadiy Rozental 2001.
   2 //  Distributed under the Boost Software License, Version 1.0.
   3 //  (See accompanying file LICENSE_1_0.txt or copy at
   4 //  http://www.boost.org/LICENSE_1_0.txt)
   5
   6 //  See http://www.boost.org/libs/test for the library home page.
   7 //
   8 //!@file
   9 //! Input iterator facade
  10 // ***************************************************************************
  11
  12 #ifndef BOOST_TEST_UTILS_INPUT_ITERATOR_FACADE_HPP
  13 #define BOOST_TEST_UTILS_INPUT_ITERATOR_FACADE_HPP
  14
  15 // Boost
  16 #include <boost/iterator/iterator_facade.hpp>
  17
  18 #include <boost/test/detail/suppress_warnings.hpp>
  19
  20 //____________________________________________________________________________//
  21
  22 namespace boost {
  23 namespace unit_test {
  24 namespace utils {
  25
  26 // ************************************************************************** //
  27 // **************          input_iterator_core_access          ************** //
  28 // ************************************************************************** //
  29
  30 class input_iterator_core_access
  31 {
  32 #if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
  33 public:
  34 #else
  35     template <class I, class V, class R, class TC> friend class input_iterator_facade;
  36 #endif
  37
  38     template <class Facade>
  39     static bool get( Facade& f )
  40     {
  41         return f.get();
  42     }
  43
  44 private:
  45     // objects of this class are useless
  46     input_iterator_core_access(); //undefined
  47 };
  48
  49 // ************************************************************************** //
  50 // **************            input_iterator_facade             ************** //
  51 // ************************************************************************** //
  52
  53 template<typename Derived,
  54          typename ValueType,
  55          typename Reference = ValueType const&,
  56          typename Traversal = single_pass_traversal_tag>
  57 class input_iterator_facade : public iterator_facade<Derived,ValueType,Traversal,Reference>
  58 {
  59 public:
  60     // Constructor
  61     input_iterator_facade() : m_valid( false ), m_value() {}
  62
  63 protected: // provide access to the Derived
  64     void                init()
  65     {
  66         m_valid = true;
  67         increment();
  68     }
  69
  70     // Data members
  71     mutable bool        m_valid;
  72     ValueType           m_value;
  73
  74 private:
  75     friend class boost::iterator_core_access;
  76
  77     // iterator facade interface implementation
  78     void                increment()
  79     {
  80         // we make post-end incrementation indefinetly safe
  81         if( m_valid )
  82             m_valid = input_iterator_core_access::get( *static_cast<Derived*>(this) );
  83     }
  84     Reference           dereference() const
  85     {
  86         return m_value;
  87     }
  88
  89     // iterator facade interface implementation
  90     bool                equal( input_iterator_facade const& rhs ) const
  91     {
  92         // two invalid iterator equals, inequal otherwise
  93         return !m_valid && !rhs.m_valid;
  94     }
  95 };
  96
  97 } // namespace utils
  98 } // namespace unit_test
  99 } // namespace boost
 100
 101 //____________________________________________________________________________//
 102
 103 #include <boost/test/detail/enable_warnings.hpp>
 104
 105 #endif // BOOST_TEST_UTILS_INPUT_ITERATOR_FACADE_HPP